I'm not sure that any of the licenses on the OSI site will do what you want. I think that's counter to their purpose.

I wonder if using the GPL would have the desired effect... commercial developers are usually rather reluctant to use GPL code because it would force them to open their own source as well. Just a thought.

BTW, why do you not want people to sell products incorporating your otherwise open code?

My thought is to let the source go. Use a restrictive license/copyright for the assets, theme, sounds, music, and original aspects. Generally nobody here is coding anything revolutionary or cutting edge as far as code goes. We aren't generally losing anything. Most of us don't write code that is clear enough or reusable enough to be used easily by an outsider without changes that require a lot of work. It's meant to learn from and to be shared, so people can more easily build on that knowledge.

Someone can not turn around and sell your game ASSETS if they are not under the license. And you can protect them any way you see fit and still enter the contest.

Plus, no matter what stage your code is in when you release YOU the developer have the edge on anyone else because you understand it best. So, anyone trying to compete with you will be at a disadvantage...

* "Do what you like" licenses, like MIT, BSD, zlib/libpng -- there are no restrictions on use beyond the "fair" ones, like misrepresentation of authorship.

* The code must remain free but you can do whatever else you like" licenses like the LGPL -- if they're careful to separate your code from theirs, they don't have to open-source their own code. They do, however, have to make changes to your code available to the public.

* The code must remain free and I have a political agenda" licenses like the GPL -- the code, any changes to it, and any programs it's used in must be released under the same license.

Of those three categories, probably the most appropriate for you is the last category. This ensures that anything anyone else does with your code will be open-source too, reducing their ability to profit from it.

It doesn't outright prevent them from selling the product, though, and as has been mentioned, things like graphics don't fall under the license, so they're free to give away the source to their program free, but charge for the assets.

BeyondCloister Wrote:I have no problem with that. I just don't want someone to take 90% code and make money from it.

I went through that thought process last year, and it occurred to me: if anyone takes my source code, builds the game and sells it, they won't make a penny. Why? Because their customers can get the same thing from me for free!

If they make substantial modifications to the source which make it more appealing to their customers than the substantial modifications I'm making to my version, then they have arguably created a separate product and it's reasonable that they should be able to charge for it.

Finally, I'm much more precious about my character designs and so on than I am the code, so I explicitly copyrighted those elements to prevent people from using them in their own games.

IIRC, last year the rules stated that entrants' games must be completely free, and shareware or commercial entries were prohibited, but that condition seems to have been dropped from this year's rules (unless I'm going blind!).

With that in mind, I presume you can do whatever you want in this respect. However, I strongly recommend you don't do (or even mention) anything which would cost players money during the contest, or you run the risk of alienating voters and ruining your chances.

It really depends. If you want anyone using your code to be forced to make it clear to the user of the software that your code is being used, then I don't think any of these licenses will protect you like that. ( They are made so that you hold no responsability whatsoever in regards to the behavior of the code ).

However, if you want to make sure that anyone reading source code derived from yours knows that it is derived from your work, then either the BSD or MIT license would be good IMHO.

There is no restrictive uDG license this year, so you're pretty much stuck with the licenses from the OSI, all of which are varying shades of unrestrictive.

You might want to read the discussion in this thread. I've already expressed my opinions on the subject there, but to summarise:

The whole purpose of the contest is that the source should be genuinely open and not merely available for reading.

You don't have to put the assets under the same license as the source code. You can put them under plain old copyright to deny people the right to reuse them. However, make sure your documentation makes it clear which things fall under which license.

Using the GPL will turn off most commercial and shareware developers from using your code, because they'd also be obliged to open their source. Beyond that, why would you want to prevent freeware authors from using your code?

I've looked at some of them. I like the simplicity of zlip/libpng. I guess the only thing I don't like about zlib is all in clause 1. There isn't a great distinction between the original software and modified software; small modifications could be made and then the person could invoke the "optional attribution" clause and not attribute the original author at all. For a code snippet this would be fine but for a complete, working application it seems a little weak.

Is there a simple license that requires attribution or thanks?

Alternatively, am I on shaky ground if I make a small modification to the license to require attribution of some kind?

Attribution Assurance looks interesting in that regard. My problems with it are, I don't know nuffin' about PGP, there is an embarrassing typo in it (GPG instead of PGP) so is anyone actually using this license? And I'd want to take out that part of the sentence in the intro about why the author wants attribution ("..thousands of dollars in otherwise billable-time..."). That figure is high for a small game, and for that matter if I spend only 15 minutes on it and wanted attribution, that would be my right.

As a side note, for those of you considering the most restrictive licenses, keep in mind that some of them could hamper your own efforts to continue developing your own game and possibly releasing it as a commercial product one day. I haven't spotted any licenses where the original developer gets rights that noone else does, aside from the ability to use their own trademarks etc. (Or am I misunderstanding these licenses?)